Manufacture of rayon threads and the like



April 2, A. J. L. MORITZ MANUFACTURE OF RAYON THREADS AND THE LIKE Filed July 26 1938 Patented Apr. 2, 1940 MANUFACTURE OF RAYON THREADS AND LIKE Adrian J. L. Moritz, Enka, N. 0., asslgnor to American Enka Corporation, Enka, N'. 0., a corporation of Delaware Application July 26, 1938, Serial No. 221,432

1 Claim.

. The present invention relates to the manufacture of rayon threads and more particularly to an improved method'and device for use in the production'of threads according to the centrifugal bucket or pot spinning process.

The normal bucketor pot spinning process involves extruding a cellulosic ,solution through a coagulating medium to form threads composed of a number of filaments. These threads are then withdrawn from the coagulating medium, stretched between driven godets in the usual manner, and collected in a rapidly rotating bucket. A thread-guide or spinning funnel is mounted for reciprocation above the axis of the bucket, and this funnel is adapted to guide the thread into the bucket in a manner to causethe thread to be laid up'in the form of a cake, due to the centrifugal force created by' rotation of the bucket.

In practicing the bucket or pot spinning process in which a standard type spinning funnel is utilized, it has been found that the thread as it is fed into the bucket from the last godet with which it contacts will normally commence wisting or ballooning at the mouth, -or-lower outlet, of the funnel, and this action is continued back to the godet wheel. Such twisting or ballooning action causes vibrations to exist in the thread which tend to disturb the smooth passage of the thread. Furthermore, due to the eccentric position assumed by portions of the thread during the ballooning thereof, acidic treating liquids are thrown therefrom. These liquids precipitate salts on the surrounding apparatus and additionally, the acids will. corrode any metallic parts with whichthey come in contact.

.The objectionable vibrating or ballooning action of the thread has another disadvantage in that it effects a variable twist in the thread; whereas, uniformity is desirable for practical pur-' poses. The twist of the ,thread, or turns per unit of length, depends on the R. P. M. of the bucket and the length of delivered thread which is subject to the twisting action at any given moment. Generally speaking, the R. P. .Mfof the bucket and the speed of delivery of the thread by the last godet contacted are constant throughout the build-up of the cake. The twisting action on the thread commencing at the outlet of the spinning funnel and extending upward until the thread contacts a material obstruction normally causes the twisting distance to vary; This is due to the fact that in the conventional spinning method the twisting distance extends from the funnel outlet to the godet, and due to the retance results. Thus, the twist per unit of length through which a freshly spun thread I2 is deciprocation of the funnel, a variable twisting disvaries.

The presentinvention contemplates the provision of an improved thread-guide funnel that 5 will overcome difliculties and disadvantagesheretofore encount'eredas a result of the use of standard funnels.

More specifically this invention contemplates the provision of a particular apparatus for per- 10 forming a novel step in the process of spinning rayon by the pot spinning method, the step involving the avoidance of ballooning of succeeding portionsof the thread to thereby attain a 'uniform twist and smooth passage of the thread .16 into the pot.

Further objects and advantages will become apparent from a consideration of the following detailed description when considered in connection with the accompanying drawing wherein: 90

Figure 1 is an illustration of a centrifugal bucket in cross-section and a godet and-standard. spinning funnel in elevation with a thread passing therebetween having the balloon effect rep- I resented by dotted lines;

Figure 2 is similar to Figure 1, except that a novel type spinning funnel as contemplated by the present invention is utilized for eliminating the balloon effect and maintaining the twisted length of the thread constantj and Figure 3 is a perspective view of the top portion of'the improved funnel.

Referring'tothe drawing, the numeral I0 indicates a centrifugal bucket of the usual type employed in the manufacture of rayon. Mounted $5 for reciprocation above the axis of rotation of the bucket is a standard spinning funnel ll scending. As indicated in Figure 1, thisthread contains a number of balloons l3 that commence 0 at the mouth of the spinning funnel and extend back 'to the godet M. This balloon formation indicates thatthis part of the thread is subject to the twisting action.

I In Figures 2 and 3 an improved spinning fun- 45 nel I5 is shown. In the upper enlarged portion of this funnel a cylindrical or oval bar I6 is detachably mounted in slots l1. Bar It may be constructed of any suitable acid-resistant ma-. terial' such as glass, Bakelite, hard rubber, et cetera. It may sometimes be desirable, in order to prevent spraying of liquids, to locate the bar farther down in the enlarged part of the funnel, in which case proper openings will be provided therefor. It is preferable to position the bar so r the upper portion of the funnel.

that it contacts the thread at a point which,'

under normal circumstances, would be adjacent the middle of one of the balloons or between the nodes. Such location tends to entirely eliminate the remaining balloons and no twisting action occurs above the bar.

In operation, during the initial spinning step when the thread is introduced into the bucket, the bar [6 may be temporarily removed from the funnel. As soon as the spinning in period is completed, the bar can be placed in position in The passage of the thread then continues ina smooth manner, as indicated in Figure 2, with the result that there is substantially no liquid sprayed from the thread, and in addition, the twist is maintained constant because it is prevented from extending above the bar and the "twisting distance", i. e., the distance from the bar to the outlet of the funnel is always the same. This distance is constant at all times, and the twist per unit length of thread remains constant as long as the speed of delivery by the godet and the speed of rotation of the bucket remain constant.

What I claim is:

A thread-guide tunnel for use in the manufacture of rayon threads and the like, comprising an elongated tubular member having an enlarged 10 upper portion with slots therein and an acid-resistant transverse bar substantially intersecting the axis of the tubular member removably mounted in said slots whereby during the initial spinning in step, the bar may be removed to 15 permit free passage of the thread through the funnel.

ADRIAN J. L. MORITZ. 

